Axial flow compressors



D. J. CLARKE AXIAL FLOW COMPRESSORS June 30, 1959 2 Sheets-Sheet l v Filed Jan. 19, 1953 June 30,1959 D J. CLARKE AXIAL. FLOW COMPRESSORS 2 Sheets-Sheet 2 Filed Jan. 19, 1953 United States Pate r 2,892,583 FLOW coMPRu'ssoRs Daniel J. Clarke, Bay City, Micln, assignor to The Stalker Corporation, a corporation of-Michigan Application January 19, 1953, Serial No. 332,009

6' Claims; (Cl. 230-134) My'in'v'ention relates'to compressors of the axial flow type. V 7 An object of the invention is to provide ayrotor hub structure upon which blade rings and spacer rings-may bestacked. V

Another object is to provide a rotor structure adapted to transmit torque to a plurality of sheet metal rings which carry blades.

Another object of the invention is to provide a rotor of light weight and low inertia about its axis.

Still another object is to provide a blade and rotor struc ture-which is adapted to sheet metal construction, particularly in large size rotors.

Still another object is to provide a sheet metal struce ture giving access to the roots of theblades for thefixing of'them to the rim structure,

The above objects are accomplished by themeans illustrated in theaccompanying drawings in which- Fig. 1 is an axial section through a compressor accordingto this invention;

Fig. 2 is a fragmentary perspective, view of a. part of the rotor; I

Fig. 3 is a perspective view of a blade with a. portion of the blade wall cut away; n

Fig. 4 is' a fragmentary section of a blade tip;

Fig, 5 is a radial View of a fragment offa rim showing blade openings;

Fig. 6 is a transverse, section through. a channel ring on line 6-6 in Fig. 5; and I Fig. 7 is a fragmentary sectionof a channel ring showing the flanges of the bladeriveted tothe channel legs.

As the tip diameter of compressor rotors increases the mass of the blades increases as the cube of the dimensions while the cross sectional'areas, such as atthe roots of the blades increase only as the square of the dimensions. Consequently thestresses in the blades tend to increase. Likewise the load on the hub structure from the blades increases leading to very heavyrotorstructures requiring expensivev machining.

In this: invention the blades are made of sheet metal and are consequently light and economical to fabricate. Because the blades have asmall weight it is practical to make the supporting rings of sheet metal resulting in low cost and small weight forthese structures.

Thelig-ht weight is also desirable in many applications where quick starts are required.

The rotor of this invention providesalso for avery rigid hub structure over which-the bladed wheels are, slid and keyed or-fixed inplace. Thus the-bladed wheel's may be removed for replacementor repair. The latter is readily accomplished because-the wheel structure is open on its inner side giving access to the root ends of the blades.

Referring to the drawings the compressor rotor in Fig. l is indicated generally at 10 and is supported on-t-he shaft 12 in bearings 16 and 18'. The case 20 houses the rotor and supports the stators 21-24.

2,892,583 Patented June 30, 1959 The rotor'd'rum' or hub is 30 and'is preferably made from a, light metal like-aluminum, titanium, or magnesium, particularly if a small inertia is desired. The drum (Fig. 2) has formed in its cylindric surface the flutes 32 defined by the splines; Blade. wheels 35--37 are carried on the drum.

The blades 40, Figs. 1-4, are assembled in the annular rim structures 42 each preferably formed by two rings 44 and 46 overlapping and joined at 48v to form a channel ring. The legs of the channels have notches 50 at their inner edges fitting over the splines 34 on the drum whereby the rim structure is keyed to the drum. Thus-the drum 30' is a hub means for engaging the annular rim'structure for transmitting torque to the blades to rotate them.

Each blade 40 comprises an envelope 60 and a stem 62 which is preferably corrugated'spanwise to form the stem flutes 64 between the stem splines66. The envelope is fixed to the stem by soldering, welding, riveting or the like.

The stem has the flanges 70a and 72, Fig. 3, protruding chordwise from openings 74 and-76 in the leading and trailing edge portions of the blades.

Each blade, extends-radially inward through an open ing 80 (Figs. 2, Sand 6) in the rim 82 of each channel ring 42. These openings have flanges81 and 83 turned radially inward and are contoured to the root section of the blade. This contour is also shown at 84 in Fig. 3.

In fabricating the rotor assembly the ring pieces 44 and 46 are pressed out and joined. together at 48to comprise the channel rings 82-. Theblades are then passed radially outward through the openings. $0; and the flanges 70 and 72 are fixed to the legs 86. and 88. This is readily accomplished' because there, is free-1 access to the interior ofthe rings. through the gap89 between the legs of'each ring.

The rings are next slid over the drum or hub 30' with the notchesISOanddrum splines interfitting.

The flanges 70 and 7 2 may be fixed to the legs by riveting, welding, soldering or-the like- Where the blade and ring structure are of such adiameterthat they may be inserted'in a-soldering furnace the flanges are preferably spot welded as at -and 102 to holdthem together while they are soldered.

When the rotors are too large or of materials not well: suitedto fusion or soldering, the parts may be fixedtogether by mechanical fastening. means such as'rivets;1;03. or bolts 105 shown in Fig. 7.

The tie rods- 1 04. pass through-the end plates 11 0'and- 11 2and the spacers 1062 serving to clamp the rings 82- together with the spacer rings-1 14" interposed.

The drum 30 is fixed to the end plate by the machine screws 116-or likemeans, thedrum extending the entire axial distance from one; end plate to the other.

The radial-lengths of the-legs of the rim-structure are preferably substantially less than one halftheradiusof the outer surface of the: drum so thatt he' bladescan be readily: connected to the inside surfaces of the legs.

Preferably theblade walls have athickness of the order of that of the ehannel rings such as- 44 and 46. The blades may have a thickness of the order or 2% of the chord length at the root ends ofthe blades. The bladewalls may, forinstance, have a thickness of 0.040 inch-- where the blade chord is 4- inches. If the blade is-not reenforced internally, the Wall thickness should be greater.

In an: axialflow machine the leading and trailing edges of the blades extend radially and the fluid isdischarged rearward in the general direction: of the axis of'rotation';

Whilel have: illustrated specific forms of the-invention; it isto beunderstood; that variations may be made therein and that I intend to claiminvention broadly as in-: di ate by he pp ncl claims I claim:

1. In an axial flow compressor, an axial flow rotor comprising an axially elongated drum mounted in said case for rotation about an axis, a light hollow channel ring of sheet metal construction forming a rim structure encircling said drum, said channel ring and said drum having slidably interfitting parts for detachably securing said ring to said drum to be rotated thereby, a plurality of axial flow blades peripherally spaced about said rim structure and extending radially outward therefrom with rotor flow passages between said blades, means for securing said blades to said channel ring radially outwardly of said drum, each said blade being of hollow sheet metal construction of light weight limiting the centrifugal loads at the roots thereof during rotation of said rotor at high tip speeds, said ring of sheet metal construction being able to sustain said centrifugal loads of said blades because of their hollow sheet metal construction limiting said loads thereof, and means for securing each of said blades to said ring radially inwardly of said rim structure and radially outwardly of said drum.

2. In combination in an axial flow compressor, an axial flow rotor comprising a drum having a spline con struction onits outer periphery and mounted for rotation about an axis, a light annular channel ring of sheet metal construction having notched legs removably received on said spline construction of said drum and rotatably secured thereto to be rotated thereby, the radial lengths of said legs being less than one-half the radius of the outer surface of said drum, a plurality of axial flow blades peripherally spaced about said ring and extending radially outward therefrom and secured thereto radially outwardly of said drum with rotor flow passages between said blades, each said blade being of sheet metal construction with an envelope wall thickness of the order of 2 percent of the chord thereof providing lightness and limiting the centrifugal load at the root thereof during rotation of said rotor, said ring of sheet metal construction being able to sustain said centrifugal loads of said blades because of their hollow sheet metal construction limiting said loads thereof.

3. In combination in an axial flow compressor, a rotor comprising a drum mounted for rotation about an axis, a light weight hollow channel ring of sheet metal construction detachably secured rotatably to said drum to be rotated thereby providing for axial removal therefrom, said ring having a rim and axially spaced legs extending radially inward therefrom defining a channel cross section, the radial lengths of the legs of said ring being less than one half the radius of the outer surface of said drum, and a plurality of hollow axial flow blades peripherally spaced about said ring and extending radially outward therefrom, said blades having root ends extend ing through said rim and secured to the inner surfaces of said legs radially outwardly of said drum, said channel cross section providing a peripheral opening between said legs for securing said blades thereto, each said blade being of hollow sheet metal construction of light weight limiting the centrifugal loads at the root thereof during rotation of said rotor at high blade tip speeds, said ring of sheet metal construction being able to sustain said centrifugal loads of said blades because of their hollow sheet metal construction limiting said loads thereof.

4. In combination in an axial flow compressor, a rotor comprising a drum mounted for rotation about an axis, a light weight hollow ring of sheet metal construction secured rotatably to said drum to be rotated thereby, said ring having a rim and axially spaced legs extending radially inward therefrom defining a channel cross section, spline means establishing a separable driving connection between said drum and said ring, and a plurality of hollow axial flow blades peripherally spaced about said ring and extending radially outward therefrom, each said blade having an internal stem extending through said rim and having flanges at the radially inner end thereof secured to said legs on the inner surfaces thereof radially outwardly of said drum, said channel cross section providing a peripheral opening between said legs for securing said stem flanges thereto, and a blade envelope fixed to and enclosing each said stern, each said blade being of hollow sheet metal construction of light weight limiting the centrifugal loads at the root thereof during rotation of said rotor at high blade tip speeds, said ring of sheet metal construction being able to sustain said centrifugal loads of said blades because of their hollow sheet metal construction limiting said loads thereof.

5. In an axial flow rotor comprising axially spaced end plates, a plurality of hollow channel rings of sheet metal construction positioned in axial alignment between said plates, each said ring having a rim and radially directed side walls spaced axially and extending radially inward therefrom, a plurality of axial flow blades peripherally spaced about the rings of said rotor stages and extending radially outward from said rim with rotor flow passages between said blades, means for securing said blades to said side walls of said channel rings inwardly of said rim, each said blade being of hollow sheet metal construction of light weight limiting the centrifugal load at the root thereof at high blade tip speeds, each said ring being able to sustain said centrifugal loads of said blades because of their hollow sheet metal construction limiting said loads thereof, a continuous drum extending from one of said end plates to the other, and spline means removably fixing said rings in assembled driving relation upon said drum between said end plates.

6. In combination in an axial flow compressor, an axial flow rotor comprising end plates, a drum extending axially from one of said end plates to the other, a plurality of axially spaced thin wall rings positioned between said plates, a plurality of axial flow blades peripherally spaced about said rings and extending radially outward therefrom and having root ends secured thereto with rotor flow passages between said blades, each said blade being of hollow sheet metal construction of light weight limiting the centrifugal load at the root thereof at high blade tip speeds, each said ring having a rim and an integral radially directed wall extending inward to a limited extent, a spline connection between the inner end of the wall of each of said rings and said drum, and means fixing said rings one relative to the other and to said end plates, said means engaging said radially directed wall of each said ring radially outward from said drum and radially inward from said root ends of said blades.

References Cited in the file of this patent UNITED STATES PATENTS 1,000,602 Jacobs Aug. 15, 1911 2,337,619 Miller Dec. 28, 1943 2,436,087 Benson Feb. 17, 1948 2,483,610 Baumann Oct. 4, 1949 2,510,606 Price June 6, 1950 2,537,739 Chilton Jan. 9, 1951 2,678,537 Stalker May 18, 1954 2,680,001 Batt June 1, 1954 2,689,682 Boyd et a1 Sept. 21, 1954 2,693,905 Carter Nov. 9, 1954 2,749,026 Hasbrouck et al June 5, 1956 2,749,028 Stalker June 5, 1956 2,801,071 Thorp II July 30, 1957 2,802,619 Clark Aug. 13, 1957 FOREIGN PATENTS 233,433 Switzerland Oct. 16,- 1944 492,801 Great Britain Sept. 27, 1938 572,859 Great Britain Oct. 26, 1945 623,710 Great Britain May 20, 1949 860,438 Germany Oct. 30, 1952 900,439 France Oct. 2, 1944 

